have vokera unica he boiler almost 4years old recently noticed pressure dropping so simply topped it up now pressure dropping to between 0 and 0.5 daily advice please my plumber simply says he will have to take all the floorboards up to find a leak he does not appear to have checked anything on the boiler itself. There is a copper pipe leading to outside wall this is dripping water outside when boiler operating Any advice please

rae, April 2013

fill system to correct water pressure and then DON'T use system for 24hrs.leave it switched OFF.if pressure holds it isn't a leak caused by pipework and rads.No water should come out of the pressure relief overflow pipe either during this test

A1, April 2013